Oracle are doing more audits period, when the licensing on SQL Server is more favourable than Oracle, more companies are looking at SSvr or OSS alternatives, Oracle want to fleece you before you leave them!
Trust me when you go through an audit with MS or Oracle and there's a lot wrong it's way more then £50k! A severe audit can easily be 6 figure sum in back payments to put it right if you're way off the mark!!